Isotopes of bromine

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Bromine (35Br) has two stable isotopes, 79Br and 81Br, with nearly equal natural abundance, and 32 known artificial radioisotopes from 68Br to 101Br, the most stable of which is 77Br, with a half-life of 57.04 hours. This is followed by 82Br at 35.282 hours and 76Br at 16.2 hours; the most stable isomer is 80mBr with the half-life of 4.4205 hours.

Quick facts Main isotopes, Decay ...
Isotopes of bromine (35Br)
Main isotopes[1] Decay
Isotope abun­dance half-life (t1/2) mode pro­duct
75Br synth 97 min β+ 75Se
76Br synth 16.2 h β+ 76Se
77Br synth 57.04 h β+ 77Se
79Br 50.6% stable
80Br synth 17.68 min β− 80Kr
β+ 80Se
80mBr synth 4.4205 h IT 80Br
81Br 49.4% stable
82Br synth 35.282 h β− 82Kr
Standard atomic weight Ar°(Br)
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Like the radioactive isotopes of iodine, radioisotopes of bromine, collectively radiobromine, can be used to label biomolecules for nuclear medicine; for example, the positron emitters 75Br and 76Br can be used for positron emission tomography.[4][5] Radiobromine has the advantage that organobromides are more stable than analogous organoiodides, and that it is not uptaken by the thyroid like iodine.[6]

List of isotopes


More information Nuclide, Z ...
Nuclide
[n 1]		 Z N Isotopic mass (Da)[7]
[n 2][n 3]		 Discovery
year[8][9]		 Half-life[1]
 Decay
mode[1]
[n 4]		 Daughter
isotope
[n 5][n 6]		 Spin and
parity[1]
[n 7][n 8]		 Natural abundance (mole fraction)
Excitation energy Normal proportion[1] Range of variation
68Br[10] 35 33 67.95836(28)# 2019 ~35 ns p? 67Se 3+#
69Br 35 34 68.950338(45) 2011 <19 ns[10] p 68Se (5/2−)
70Br 35 35 69.944792(16) 1978 78.8(3) ms β+ 70Se 0+
β+, p? 69As
70mBr 2292.3(8) keV 1981 2.16(5) s β+ 70Se 9+
β+, p? 69As
71Br 35 36 70.9393422(58) 1982 21.4(6) s β+ 71Se (5/2)−
72Br 35 37 71.9365946(11) 1970 78.6(24) s β+ 72Se 1+
72mBr 100.76(15) keV 1982 10.6(3) s IT 72Br (3−)
β+? 72Se
73Br 35 38 72.9316734(72) 1970 3.4(2) min β+ 73Se 1/2−
74Br 35 39 73.9299103(63) 1953 25.4(3) min β+ 74Se (0−)
74mBr 13.58(21) keV 1974 46(2) min β+ 74Se 4+
75Br 35 40 74.9258106(46) 1948 96.7(13) min β+ (76%)[6] 75Se 3/2−
EC (24%) 75Se
76Br 35 41 75.924542(10) 1952 16.2(2) h β+ (57%)[6] 76Se 1−
EC (43%) 76Se
76mBr 102.58(3) keV 1978 1.31(2) s IT (>99.4%) 76Br (4)+
β+ (<0.6%) 76Se
77Br 35 42 76.9213792(30) 1948 57.04(12) h EC (99.3%)[11] 77Se 3/2−
β+ (0.7%) 77Se
77mBr 105.86(8) keV 1972 4.28(10) min IT 77Br 9/2+
78Br 35 43 77.9211459(38) 1937 6.45(4) min β+ (>99.99%) 78Se 1+
β− (<0.01%) 78Kr
78mBr 180.89(13) keV 1961 119.4(10) μs IT 78Br (4+)
79Br 35 44 78.9183376(11) 1920 Stable 3/2− 0.5065(9)
79mBr 207.61(9) keV 1962 4.85(4) s IT 79Br 9/2+
80Br 35 45 79.9185298(11) 1937 17.68(2) min β− (91.7%) 80Kr 1+
β+ (8.3%) 80Se
80mBr 85.843(4) keV 1937 4.4205(8) h IT 80Br 5−
81Br[n 9] 35 46 80.9162882(10) 1920 Stable 3/2− 0.4935(9)
81mBr 536.20(9) keV 1965 34.6(28) μs IT 81Br 9/2+
82Br 35 47 81.9168018(10) 1937 35.282(7) h β− 82Kr 5−
82mBr 45.9492(10) keV 1965 6.13(5) min IT (97.6%) 82Br 2−
β− (2.4%) 82Kr
83Br 35 48 82.9151753(41) 1937 2.374(4) h β− 83Kr 3/2−
83mBr 3069.2(4) keV 1989 729(77) ns IT 83Br (19/2−)
84Br 35 49 83.9165136(17)[12] 1943 31.76(8) min β− 84Kr 2−
84m1Br 193.6(15) keV[12] 1960 6.0(2) min β− 84Kr (6)−
84m2Br 408.2(4) keV (1970)[n 10] <140 ns IT 84Br 1+
85Br 35 50 84.9156458(33) 1943 2.90(6) min β− 85m1Kr[13] 3/2−
86Br 35 51 85.9188054(33) 1962 55.1(4) s β− 86Kr (1−)
87Br 35 52 86.9206740(34) 1943 55.68(12) s β− (97.40%) 87Kr 5/2−
β−, n (2.60%) 86Kr
88Br 35 53 87.9240833(34) 1949 16.34(8) s β− (93.42%) 88Kr (1−)
β−, n (6.58%) 87Kr
88mBr 270.17(11) keV 1970 5.51(4) μs IT 88Br (4−)
89Br 35 54 88.9267046(35) 1959 4.357(22) s β− (86.2%) 89Kr (3/2−, 5/2−)
β−, n (13.8%) 88Kr
90Br 35 55 89.9312928(36) 1959 1.910(10) s β− (74.7%) 90Kr
β−, n (25.3%) 89Kr
91Br 35 56 90.9343986(38) 1974 543(4) ms β− (70.5%) 91Kr 5/2−#
β−, n (29.5%) 90Kr
92Br 35 57 91.9396316(72) 1974 314(16) ms β− (66.9%) 92Kr (2−)
β−, n (33.1%) 91Kr
β−, 2n? 90Kr
92m1Br 662(1) keV (2012)[n 11] 88(8) ns IT 92Br
92m2Br 1138(1) keV (2012)[n 11] 85(10) ns IT 92Br
93Br 35 58 92.94322(46) 1988 152(8) ms β−, n (64%) 92Kr 5/2−#
β− (36%) 93Kr
β−, 2n? 91Kr
94Br 35 59 93.94885(22)# 1988 70(20) ms β−, n (68%) 93Kr 2−#
β− (32%) 94Kr
β−, 2n? 92Kr
94mBr 294.6(5) keV 2012 530(15) ns IT 94Br
95Br 35 60 94.95293(32)# 1997 80# ms [>300 ns] β−? 95Kr 5/2−#
β−, n? 94Kr
β−, 2n? 93Kr
95mBr 537.9(5) keV 2012 6.8(10) μs IT 95Br
96Br 35 61 95.95898(32)# 1997 20# ms [>300 ns] β−? 96Kr
β−, n? 95Kr
β−, 2n? 94Kr
96mBr 311.5(5) keV 2012 3.0(9) μs IT 96Br
97Br 35 62 96.96350(43)# 1997 40# ms [>300 ns] β−? 97Kr 5/2−#
β−, n? 96Kr
β−, 2n? 95Kr
98Br 35 63 97.96989(43)# 2010 15# ms [>400 ns] β−? 98Kr
β−, n? 97Kr
β−, 2n? 96Kr
99Br[14] 35 64 2024
100Br[14] 35 65 2024
101Br[15] 35 66 2021
This table header & footer:
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  1. [1]
    mBr – Excited nuclear isomer.
  2. [2]
    ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. [3]
    # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. [4]
    Modes of decay:
    IT:Isomeric transition
    n:Neutron emission
    p:Proton emission
  5. [5]
    Bold italics symbol as daughter – Daughter product is nearly stable.
  6. [6]
    Bold symbol as daughter – Daughter product is stable.
  7. [7]
    ( ) spin value – Indicates spin with weak assignment arguments.
  8. [8]
    # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  9. [9]
    Fission product
  10. [10]
    Half-life not measured, only upper limit.
  11. [11]
    Half-life shorter than 100ns, not included in discovery database

Bromine-75

Bromine-75 has a half-life of 97 minutes.[16] This isotope undergoes positron emission rather than electron capture about 76% of the time,[6] so it was used for diagnosis and positron emission tomography (PET) in the 1980s.[4] However, its decay product, selenium-75, produces secondary radioactivity with a longer half-life of around 120 days.[6][4]

Bromine-76

Bromine-76 has a half-life of 16.2 hours.[16] While its decay is more energetic than 75Br and has a lower yield of positrons, about 57% of decays,[6] bromine-76 has been preferred in PET applications since the 1980s because of its longer half-life and easier synthesis, and because its decay product, 76Se, is not radioactive.[5]

Bromine-77

Bromine-77 is the most stable radioisotope of bromine, with a half-life of 57.04 hours.[16] Although β+ decay is possible for this isotope, about 99.3% of decays are by electron capture.[11] Despite its complex emission spectrum, featuring strong gamma-ray emissions at 239, 297, 521, and 579 keV,[17] 77Br was used in SPECT imaging in the 1970s.[18] However, except for longer-term tracing,[6] this is no longer considered practical due to the difficult collimator requirements and the proximity of the 521 keV line to the 511 keV annihilation radiation related to the β+ decay.[18] The Auger electrons emitted during decay are nevertheless well-suited for radiotherapy, and 77Br can possibly be paired with the imaging-suited 76Br (produced as an impurity in common synthesis routes) for this application.[4][18]

See also

Daughter products other than bromine

References

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